Pleasedon't throw your cigarette butts on the ground or out the window of your car. Since they're made of cellulose acetate, a kind of plastic, they don'treally biodegrade, and I've spent enough of my life cleaning them up off of floors and sidewalks to just absolutely hate the sight of them. In the vast majority of cases, I'd guessthat you're not actually toobusy and important to throw them in the trash.